The present invention relates to dyeing and marking agents containing a dye in solution in a liquid medium which consists either completely or predominantly of one or several organic solvents.
Dyeing agents, for example, black ink having a dye content of about 2.4% by weight (referred to the solution) are known, with which color contrasts having a PCS-value of about 0.6 can be obtained. Deepening the color by increasing the dye content often is not possible because of the limited solubility of the dye. The dye generally contains salts produced in the manufacture thereof and extenders such as sodium carbonate, sodium sulfate and sodium chloride. While the use of non-extended or pure dyes permits dye concentrations of about 5%, the solutions of such dyes in media with predominantly organic solvents have a very aggressive behavior vis-a-vis metals and, for example, attack pure nickel. With predominantly aqueous media, the drying times are excessively long.
It is further known that by adding solubilizers with alkaline action such as amines (for example, morpholine, isophoronediamine, pyridine) and alcohol amines, (for example, ethanol amines, dimethylamino ethanol) an increase in the concentration of the dye in the dye solution of up to 15% by weight can be obtained. Such additives, however, do not prevent corrosion. In addition, many of the added amines and alcohol amines have a very disagreeable odor which is absorbed by the material to be dyed and also evaporate from fibers only after a long period of time.